[llvm] 6f89cbc - LowerDbgDeclare: look through bitcasts.
Evgenii Stepanov via llvm-commits
llvm-commits at lists.llvm.org
Thu Dec 5 11:24:45 PST 2019
Author: Evgenii Stepanov
Date: 2019-12-05T11:19:07-08:00
New Revision: 6f89cbc429f8459321733f2ae357f508a62b0df6
URL: https://github.com/llvm/llvm-project/commit/6f89cbc429f8459321733f2ae357f508a62b0df6
DIFF: https://github.com/llvm/llvm-project/commit/6f89cbc429f8459321733f2ae357f508a62b0df6.diff
LOG: LowerDbgDeclare: look through bitcasts.
Summary:
Emit a value debug intrinsic (with OP_deref) when an alloca address is
passed to a function call after going through a bitcast.
This generates an FP or SP-relative location for the local variable in
the following case:
int x;
use((void *)&x;
Reviewers: aprantl, vsk, pcc
Subscribers: hiraditya, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D70752
Added:
llvm/test/Transforms/Util/dbg-call-bitcast.ll
Modified:
llvm/lib/Transforms/Utils/Local.cpp
Removed:
################################################################################
diff --git a/llvm/lib/Transforms/Utils/Local.cpp b/llvm/lib/Transforms/Utils/Local.cpp
index eaccaa1c4ac5..41f1dd951a84 100644
--- a/llvm/lib/Transforms/Utils/Local.cpp
+++ b/llvm/lib/Transforms/Utils/Local.cpp
@@ -1421,22 +1421,32 @@ bool llvm::LowerDbgDeclare(Function &F) {
}))
continue;
- for (auto &AIUse : AI->uses()) {
- User *U = AIUse.getUser();
- if (StoreInst *SI = dyn_cast<StoreInst>(U)) {
- if (AIUse.getOperandNo() == 1)
- ConvertDebugDeclareToDebugValue(DDI, SI, DIB);
- } else if (LoadInst *LI = dyn_cast<LoadInst>(U)) {
- ConvertDebugDeclareToDebugValue(DDI, LI, DIB);
- } else if (CallInst *CI = dyn_cast<CallInst>(U)) {
- // This is a call by-value or some other instruction that takes a
- // pointer to the variable. Insert a *value* intrinsic that describes
- // the variable by dereferencing the alloca.
- DebugLoc NewLoc = getDebugValueLoc(DDI, nullptr);
- auto *DerefExpr =
- DIExpression::append(DDI->getExpression(), dwarf::DW_OP_deref);
- DIB.insertDbgValueIntrinsic(AI, DDI->getVariable(), DerefExpr, NewLoc,
- CI);
+ SmallVector<const Value *, 8> WorkList;
+ WorkList.push_back(AI);
+ while (!WorkList.empty()) {
+ const Value *V = WorkList.pop_back_val();
+ for (auto &AIUse : V->uses()) {
+ User *U = AIUse.getUser();
+ if (StoreInst *SI = dyn_cast<StoreInst>(U)) {
+ if (AIUse.getOperandNo() == 1)
+ ConvertDebugDeclareToDebugValue(DDI, SI, DIB);
+ } else if (LoadInst *LI = dyn_cast<LoadInst>(U)) {
+ ConvertDebugDeclareToDebugValue(DDI, LI, DIB);
+ } else if (CallInst *CI = dyn_cast<CallInst>(U)) {
+ // This is a call by-value or some other instruction that takes a
+ // pointer to the variable. Insert a *value* intrinsic that describes
+ // the variable by dereferencing the alloca.
+ if (!CI->isLifetimeStartOrEnd()) {
+ DebugLoc NewLoc = getDebugValueLoc(DDI, nullptr);
+ auto *DerefExpr =
+ DIExpression::append(DDI->getExpression(), dwarf::DW_OP_deref);
+ DIB.insertDbgValueIntrinsic(AI, DDI->getVariable(), DerefExpr,
+ NewLoc, CI);
+ }
+ } else if (BitCastInst *BI = dyn_cast<BitCastInst>(U)) {
+ if (BI->getType()->isPointerTy())
+ WorkList.push_back(BI);
+ }
}
}
DDI->eraseFromParent();
diff --git a/llvm/test/Transforms/Util/dbg-call-bitcast.ll b/llvm/test/Transforms/Util/dbg-call-bitcast.ll
new file mode 100644
index 000000000000..6625b469b06e
--- /dev/null
+++ b/llvm/test/Transforms/Util/dbg-call-bitcast.ll
@@ -0,0 +1,48 @@
+; RUN: opt -instcombine -S %s | FileCheck %s
+
+define dso_local void @_Z1fv() {
+ %1 = alloca i32, align 4
+ %2 = bitcast i32* %1 to i8*
+ call void @llvm.lifetime.start.p0i8(i64 4, i8* nonnull %2)
+ call void @llvm.dbg.declare(metadata i32* %1, metadata !16, metadata !DIExpression()), !dbg !19
+; CHECK: %[[A:.*]] = alloca i32, align 4
+; CHECK: call void @llvm.dbg.value(metadata i32* %[[A]], {{.*}}, metadata !DIExpression(DW_OP_deref)
+; CHECK: call void @_Z1gPv
+ call void @_Z1gPv(i8* nonnull %2)
+ %3 = bitcast i32* %1 to i8*
+; CHECK: call void @llvm.dbg.value(metadata i32* %[[A]], {{.*}}, metadata !DIExpression(DW_OP_deref)
+; CHECK: call void @_Z1gPv
+ call void @_Z1gPv(i8* nonnull %3)
+ call void @llvm.lifetime.end.p0i8(i64 4, i8* nonnull %2)
+ ret void, !dbg !21
+}
+
+declare void @llvm.lifetime.start.p0i8(i64 immarg, i8* nocapture)
+declare void @llvm.dbg.declare(metadata, metadata, metadata)
+declare dso_local void @_Z1gPv(i8*)
+declare void @llvm.lifetime.end.p0i8(i64 immarg, i8* nocapture)
+
+!llvm.dbg.cu = !{!0}
+!llvm.module.flags = !{!8, !9, !10}
+
+!0 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus_14, file: !1, producer: "clang version 10.0.0 (git at github.com:llvm/llvm-project.git cab64b5708f614c71d275ec9d134e68b8c3baedd)", isOptimized: true, runtimeVersion: 0, emissionKind: FullDebug, enums: !2, retainedTypes: !3, nameTableKind: None)
+!1 = !DIFile(filename: "dbg.cc", directory: "/tmp")
+!2 = !{}
+!3 = !{!4, !5}
+!4 = !DIDerivedType(tag: DW_TAG_pointer_type, baseType: null, size: 64)
+!5 = !DISubprogram(name: "g", linkageName: "_Z1gPv", scope: !1, file: !1, line: 1, type: !6, flags: DIFlagPrototyped, spFlags: DISPFlagOptimized, retainedNodes: !2)
+!6 = !DISubroutineType(types: !7)
+!7 = !{null, !4}
+!8 = !{i32 7, !"Dwarf Version", i32 4}
+!9 = !{i32 2, !"Debug Info Version", i32 3}
+!10 = !{i32 1, !"wchar_size", i32 4}
+!12 = distinct !DISubprogram(name: "f", linkageName: "_Z1fv", scope: !1, file: !1, line: 2, type: !13, scopeLine: 2, flags: DIFlagPrototyped | DIFlagAllCallsDescribed, spFlags: DISPFlagDefinition | DISPFlagOptimized, unit: !0, retainedNodes: !15)
+!13 = !DISubroutineType(types: !14)
+!14 = !{null}
+!15 = !{!16}
+!16 = !DILocalVariable(name: "x", scope: !12, file: !1, line: 3, type: !17)
+!17 = !DIBasicType(name: "int", size: 32, encoding: DW_ATE_signed)
+!18 = !DILocation(line: 3, column: 3, scope: !12)
+!19 = !DILocation(line: 3, column: 7, scope: !12)
+!20 = !DILocation(line: 4, column: 3, scope: !12)
+!21 = !DILocation(line: 5, column: 1, scope: !12)
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